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The reproductive aspects of Hemiramphus brasiliensis were analyzed with a view to verify the temporal dynamics of reproduction. This paper presents data on sex ratio, length at first sexual maturity, macroscopic and histological aspects of gonad development, gonadosomatic index GSI , reproductive period, and fecundity of H.
The fishes were captured from the coastal waters of Rio Grande do Norte, northeastern Brazil. Females of this species predominated in the sampled population and were larger in size than the males. The length at the first sexual maturation of males was The macroscopic characteristics of the gonads indicated four maturation stages. Histological studies of gonads of H.
The microscopic characteristics of gonad development indicate that H. Reproductive strategies of fish are used to maximize production and ensure the survival of offspring to adulthood.
Each strategy is expressed by various tactics, such as size at first maturation, fecundity, and spawning period, which are considered as important information for making rational measures to regulate fishing and conservation of fish stocks [ 1 , 2 ]. Studies on the life history of the animals show that r-strategists are characterized by small body size with early first sexual maturity, whereas the K-strategists have long lifespan, large body size, and late sexual maturity [ 3 — 5 ].
Kawasaki [ 6 , 7 ] suggested that the grouping of life history traits of marine fishes differed from the traditional r- and K-strategists developed for terrestrial animals [ 3 , 5 ], As such, a third intermediary group was suggested for marine fish characterized by long lifespan with large body size and early sexual maturity [ 6 , 7 ].
Clusters of life history strategies based on 16 characteristics using a large sample of species of marine and freshwater fish from North America were developed [ 8 ]. Later, they made a selection of five life history traits for 82 species of freshwater and 65 marine fishes and suggested a model of three strategies: 1 opportunistic strategists with small body size, early first sexual maturity, and short-life span; 2 periodic or seasonal strategists of big body size with long life span and high to intermediate fecundity; and 3 equilibrium strategists of intermediate size in relatively stable environment [ 2 ].
The fishes popularly known as ballyhoo half beak belong to the family Hemiramphidae [ 9 ] and are found in shallow marine and estuarine waters in the Atlantic, Indian, and Pacific Oceans [ 10 ].
The following species have been registered in the coastal waters of Brazil: Hemiramphus brasiliensis , Hemiramphus balao , Hyporhamphus roberti , Hyporhamphus unifasciatus , Euleptorhamphus velox , Hyporhamphus coroa, and Hyporhamphus salvatoris [ 11 ]. Among these species, H. Two halfbeak species, ballyhoo, H. It was observed that both halfbeak species spawned throughout the fishing grounds of south Florida [ 14 ].
Reproductive biology of H. Another study examined the development, reproduction, and symbiosis of an isopod parasite associated with its host H. Considering the importance of H. Artisanal fishing is the main economic activity of this municipality, producing a wide variety of commercially important marine fish, such as the flying fish, Hirundichthys affinis ; dolphinfish, Coryphaena hippurus; yellowfin tuna, Thunnus albacares; black grouper, Mycteroperca bonaci; lane snapper, Lutjanus synagris; mutton snapper, L.
In addition, small inshore fish such as the ballyhoo halfbeak, H. These fish are captured by local fishermen using different types of fishing crafts and nets [ 17 ]. The inshore waters have gradually sloping sandy banks, covered by macroalgal vegetation. Fish samples were captured with the help of local artisanal fishermen, who used small traditional fishing boats and the ballyhoo fishing nets.
Other small fish species captured were discarded. During the months of September and December fish were not captured, due to the strong winds that prevailed which prevented the fishermen from fishing activities.
Each fish was dissected and sex was identified based on the macroscopic characteristics of the gonads [ 20 ]. The gonad weight was measured to the nearest 0. The -test was utilized to check the difference between the total body length and weight of males and females [ 21 ]. The location and general aspects of the gonads were observed and stage of reproductive maturity was determined using a macroscopic staging system.
The features used for the macroscopic classification of gonads were based on the following external aspects: size, shape, color, presence of blood vessels, stiffness, and the space occupied in the coelomic body cavity [ 23 ].
In order to avoid possible variation in the developmental stage of oocytes, due to their position in the ovaries, histological examinations were carried out on sections from the anterior cephalic , middle central , and posterior caudal regions of 20 ovaries in different developmental stages [ 24 ].
These data were later compared in order to determine whether samples taken from midsection of the ovary of either lobe were representative of oocyte development. Gonadal developmental stages were assessed microscopically with the help of light microscope Taimin, model TM , coupled with a video camera Kodo Digital. The terminology used for staging of oogenesis was based on existing information [ 25 — 28 ]. The gonad was weighed to the nearest 0.
Regression analysis was utilized to check the correlation between body weight of females and fecundity and weight of ovary and fecundity. Reproductive period was determined by the temporal relative frequency distribution of the different stages of ovarian maturation [ 14 , 30 , 31 ].
A total of fishes were captured males and females. Figures 1 a and 1 b show the distribution of total length and total body weight of males and females, respectively. The individuals of H. The results indicate that females are bigger and heavier than males due to their gonads which tend to have higher mass compared to the testicles, thus agreeing with the results for the same species in South Florida [ 14 , 33 ]. In this study the sex ratio of H. The distribution of the monthly frequency of occurrence of males and females shows significant difference in the sex ratio of H.
The sex ratio could be affected by various factors related to fishery, season of the year, shoals in the feeding, and spawning areas [ 34 — 36 ]. Information on sex ratio is important for understanding the relationship between individuals, the environment, and the state of the population [ 37 ]. The total length at first sexual maturity was The males of H.
Length at maturity could either be directly affected by changes in the quantity of energy reserves available for gonad development [ 42 ] or be indirectly affected by the changes in growth, which influence the onset of gonadal maturation [ 43 ]. The females of H. The ovaries and testes were paired bilobed structures, symmetrical, elongated, and joint in the posterior part to form a short duct leading to the urogenital pore. They were located in the posterior-dorsal part of the coelomic cavity, ventral to the kidneys and swim bladder.
The immature testes were small and translucent. Maturing testes were more developed and were whitish in color. The mature testes were white and spent testes were flaccid and brown in color with hemorrhagic appearance. During maturation, the ovaries were pinkish to light orange in color and developed progressively by increasing in size and vascularization.
The mature ovaries were turgid with numerous big oocytes visible to the naked eye, and the partially spent ovaries were flaccid. These results are similar to those registered for three fish species of the family Hemiramphidae from the coastal waters of Australia [ 10 ]. Microscopic observations of the ovaries of H. Six different phases of oocyte development were observed Figure 4.
The pre vitellogenic phase of immature females included the young germinative cell phase of the reserve stock Phase I. The vitellogenic stage included the beginning of lipid deposition Phase II , lipid vitellogenic phase Phase III of maturing females, lipid and protein vitellogenic phase Phase IV , complete vitellogenesis phase Phase V , and hydrated oocyte phase Phase VI of mature females.
Postovulatory follicles were also observed. Phase II: initially the nucleus was in the center, with one or two nucleoli intensely basophilic with a well-defined cytoplasm. The nucleoli became more in number and were present in the periphery of the nucleus.
Phase III beginning of lipid deposition : this stage was characterized by small yolk vesicles in the cytoplasm. Phase IV lipid vitellogenic phase : the oocytes showed the central nucleus, cytoplasm was less basophilic than in the previous phase and with vacuoles representing the lipid deposition.
Phase V lipid and protein vitellogenic phase : besides the lipid droplets, the oocytes showed the deposition of protein in the form of platelets in the cytoplasm.
Phase VI complete vitellogenesis phase : in this stage the lipidic droplets were not observed and the protein granules were bigger in size.
The basophilic color of the cytoplasm disappeared totally and the nucleus migrated. Hydrated oocytes were highly modified; the cytoplasm was hydrated, which resulted in the adhesion of the yolk granules. Postovulatory follicles: the follicular cells were condensed, entering the space which was occupied earlier by the oocytes, thus constituting a body formed by cellular chords, folded in all directions. The oocyte development of H.
Histological analyses indicated four developmental phases of the spermatogonia in H. In an earlier study of the ballyhoo, H. In the present study, it was observed that the testicles of maturing males had spermatogonia and developing germinative cells. In mature males the testis lobules were full of spermatogonia and there was a reduction in the diameter size of tubules of spent fish with residual spermatogonia.
The development was consistent along the whole length of the testis depending on the degree of maturation. The microscopic characteristics of gonad development of H. The batch fecundity of H. Figure 6 shows the relationship between fecundity and body weight of mature females and between fecundity and gonad weight g. Fecundity increased with bigger body size and also with increasing gonad weight. Fecundity is a specific reproductive tactic [ 23 ] and is adapted to the life cycle conditions of the species [ 45 ], varying with growth, population density, body size, food availability, and mortality rate [ 33 ].
The life-history traits that typically represent trade-offs in evolutionary terms are balanced, so that the lifetime egg production of H. The mean monthly values of GSI of maturing and mature females are shown in Figure 7 a. The GSI of mature females presents the highest value during the month of April.
Frequency of monthly gonadal maturation stages of females indicates that mature females occur throughout the year Figure 7 b. The results of the present paper are similar to the earlier findings [ 14 ], since the highest GSI of mature females was in April. This study indicates that females predominate in the sampled population of H. The females were larger in size than the males; however, the males attained sexual maturity earlier than the females.
The macroscopic gonadal stages coupled with histological analysis reflect the spawning activities of H. A study on otoliths indicated that H. Based on the age and reproductive aspects of this species small size, early maturity, and short life span it is considered as an opportunistic strategist. This study provides information on the reproductive aspects, such as sex ratio, length at first sexual maturity, gonad development, and fecundity besides the reproductive strategy of H.
This study confirms that the females of H. The macroscopic characteristics of the gonads indicate four maturation stages.
Species: Hemiramphus brasiliensis, Ballyhoo halfbeak
The reproductive aspects of Hemiramphus brasiliensis were analyzed with a view to verify the temporal dynamics of reproduction. This paper presents data on sex ratio, length at first sexual maturity, macroscopic and histological aspects of gonad development, gonadosomatic index GSI , reproductive period, and fecundity of H. The fishes were captured from the coastal waters of Rio Grande do Norte, northeastern Brazil. Females of this species predominated in the sampled population and were larger in size than the males. The length at the first sexual maturation of males was
The ballyhoo halfbeak or ballyhoo Hemiramphus brasiliensis is a baitfish of the halfbeak family Hemiramphidae. It is similar to the Balao halfbeak H. Ballyhoo are frequently used as cut bait and for trolling purposes by saltwater sportsmen. Also known as balahu , redtailed balao , and yellowtail ballyhoo , ballyhoo can be seen above the waters skimming the surface to escape from their predators. The appearance is similar to skipping stones on the water. The body shows typical halfbeak shape with an elongated lower jaw and cylindrical elongated body.